Brake for an open-end spinning rotor

ABSTRACT

A rotor brake ( 8 ) for an open-end spinning rotor rotating at a high speed in a rotor housing. The open-end spinning rotor is rotatably supported by its rotor shaft ( 2 ) in the bearing nip ( 3 ) of a support-disk bearing ( 4 ). The rotor brake ( 8 ), which is preferably designed in a tong-like manner, comprises brake levers ( 9, 10 ) that can be placed on the rotor shaft ( 2 ) and comprise a replaceable brake lining ( 16 ) on their end. The brake lining ( 6 ) is manufactured from sintered bronze.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of German Application 10100524.5, filed Jan. 8, 2001, herein incorporated by reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to brakes for open-end spinning rotors and, more particularly, to such a brake for a spinning rotor which rotates at a high speed in a rotor housing and is rotatably supported by its rotor shaft in the bearing nip of a support-disk bearing and wherein the brake comprises at least one brake lever having a brake lining that can be placed on the rotor shaft upon actuation of the brake.

BACKGROUND OF THE INVENTION

[0003] Open-end rotor spinning devices of the above-indicated type with braking devices that act on the rotor shaft of the spinning means are known in various embodiments and have long been known in the state of the art.

[0004] For example, German Patent Disclosure DE 36 30 256 A1 discloses a brake for an open-end spinning rotor wherein the brake comprises a brake lever, having a brake lining, that can be adjusted from below against the rotor shaft and wherein the brake comprises two press pads with cheeks similar to brake linings which pads act from above on the rotor shaft. The cheeks of the press pads have a different coefficient of friction than the brake lining arranged on the brake lever.

[0005] Moreover, German Patent Disclosure DE 38 20 328 C2 teaches a rotor brake with tong arms arranged with specular symmetry. Each of the tong arms comprises an asbestos-free brake lining on the end. When the brake is actuated, the brake linings are placed on the rotor shaft at the same time, bringing the spinning rotor rotating at a high speed during the spinning operation to a standstill.

[0006] However, these known rotor brakes have the disadvantage that the service life of such brakes is relatively limited on account of the high loading of the brake linings. That is, the frictional heat produced during the braking procedure allows the brake linings, that consist of a metallic, fiber-reinforced material bound to an artificial resin and free of asbestos and solvent, to become smooth in time in the area of their contact site with the rotor shaft.

[0007] Such smooth brake linings have a significantly adverse effect on the operation of the brake since they result in distinctly longer braking times and a measurable loss of efficiency of the entire open-end spinning machine. In addition, there is always the danger in the case of smooth brake linings that the spinning-start carriage supplying the open-end spinning machine might stop at a spinning head whose spinning rotor has not yet been completely braked. In this instance, the service units of the spinning-start carriage as well as the open-end spinning device could experience significant damage.

[0008] In order to eliminate the above-described disadvantages, the use of brake linings consisting of a carbon fiber composite material has therefore already been suggested.

[0009] As disclosed in German Patent Disclosure DE 198 02 655 A1, such carbon fiber composite materials have the great advantage that they are extremely resistant to temperature changes and, in addition, have a very high wear resistance. Thus, in the case of brake linings consisting of carbon-containing material, the disadvantage of surface changes known from practice does not occur even after a rather long run time, so that such brake linings assure that the rotor brake always has a uniformly high braking action over its entire service life.

[0010] However, brake linings consisting of a carbon fiber composite material have the disadvantage of being relatively more expensive.

[0011] It was not possible in the past to manufacture brake linings from a carbon fiber composite material at a price that justified a serious use of such brake linings in textile machines.

SUMMARY OF THE INVENTION

[0012] It is accordingly an object of the present invention to improve the rotor brakes of an open-end spinning machine, especially their brake linings.

[0013] The present invention addresses this objective by providing a brake for an open-end spinning rotor that rotates at a high speed in a rotor housing and is rotatably supported by a rotor shaft in a bearing nip of a support-disk bearing. The brake comprises at least one brake lever having a brake lining manufactured from sintered bronze. The brake lever can be placed on the rotor shaft upon actuation of the brake.

[0014] Further advantageous embodiments of the present invention are set forth in more detail herein.

[0015] The use of a brake lining of sintered bronze has the advantage that such a material is extremely resistant to temperature changes and also exhibits a very high wear resistance. Since brake linings of sintered bronze are, in addition, considerably more economical to manufacture than brake linings of carbon-containing material. Such brake linings have the advantages of the known brake linings without their disadvantages. For example, surface changes do not occur in brake linings of sintered bronze, even after a rather long run time, so that it is assured that the rotor brakes of the open-end spinning machine have a uniformly high braking action over their entire service life at a reasonable cost.

[0016] The brake linings can preferably be fixed via a screw bolt and a fastening nut in a readily replaceable manner to the associated brake levers so that when needed a worn brake lining can be removed simply by loosening the screw bolt without problems and replacing it with a new brake lining.

[0017] Another preferred embodiment of the present invention is that the brake lining has a downward-opening fastening slot into which a centering extension of the fastening nut fits in the assembled state. That is, the brake lining can be simply drawn up by the brake lever for replacement after the screw bolt has been loosened, during which the screw bolt and the fastening nut remain in their assembled state. The assembly of the new brake lining proceeds just as simply. In this instance, the brake lining is lowered with its fastening slot from above, over the screw bolt, and the centering extension of the fastening nut and the screw bolt is subsequently retightened.

[0018] Further details of the invention can be gathered from a non-limiting exemplary embodiment presented in the following description with reference made to the drawings.

DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a schematic view of an open-end rotor spinning device with a tong-like rotor brake as well as with brake linings detachably arranged on the brake levers and manufactured from sintered bronze.

[0020]FIG. 2 is an enlarged view of a brake lever with a brake lining in accordance with the present invention.

[0021]FIG. 3 is a front view of a brake lining with fastening nut in accordance with the present invention.

[0022]FIG. 4 is a side view of the brake lining according to FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The open-end rotor spinning device 1 shown in FIG. 1 is equipped with a known spinning means, a so-called spinning rotor (not shown in detail), which is rotatably supported by its rotor shaft 2 in bearing nip 3 of support disk bearing 4.

[0024] Such a support disk bearing, that has long been known in conjunction with an open-end rotor spinning device, typically comprises two support disk pairs with front and rear support disks 7 connected via shaft 5 in such a manner as to rotate in unison, which shaft is rotatably supported in roller bearings 6 such as ball bearings.

[0025] As is indicated in FIG. 1, rotor brake 8 is in the form of a tong having arms which can be positioned on rotor shaft 2. The tong arms of rotor brake 8 are designed as brake levers 9, 10 that are supported in pivot shafts 11, 12 in such a manner that they can rotate in a limited manner and are urged by an interposed spring element 25 into an open non-braking position.

[0026] As shown in FIG. 2, brake levers 9, 10 each have a bearing 13 on the end. Brake lining 16 manufactured from sintered bronze is fastened in a replaceable manner to these bearings 13 via screw bolt 14 and fastening nut 26.

[0027] Brake levers 9, 10 each have sliding surface 18 on their end opposite brake lining 16. Sliding surfaces converge toward one another in the assembled state. Preferably roller-like pressure element 19 contacts sliding surfaces 18, which element 19 is mounted so that it can shift in direction B and at the same time move brake levers 9, 10 counter to the force of spring element 25 in a braking direction toward contact with the rotor shaft 2.

[0028] Pressure element 19 is preferably fixed between the side walls of U-shaped actuating lever 20 which is mounted in a manner such that it can rotate in a limited manner about pivot axis 21.

[0029] In addition, leaf spring 22 is fastened to actuating lever 20 and comprises catch ring 23 on its end. An actuating linkage (not shown) contacts this catch ring 23, which linkage is loaded in case of service by a movable service unit, a so-called spinning-start carriage, that automatically supplies the open-end rotor spinning devices.

[0030] As is evident from FIG. 3, in particular, brake lining 16 is essentially rectangular when viewed from the front and the comers are rounded off. Moreover, downwardly-opening fastening slot 15 is located on the bottom of brake lining 16, as shown in FIG. 4. Fastening nut 26 engages with its centering extension 17 into this fastening slot 15 in the assembled state. That is, brake lining 16 can be fixed in a non-positive manner on brake levers 9, 10 by screw bolts 14 and associated fastening nut 26 and can therefore be readily removed from the particular bearing 13 if required and replaced by a new brake lining 16.

[0031] It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. 

What is claimed is:
 1. A brake for an open-end spinning rotor rotatably supported for high speed rotation in a rotor housing by a rotor shaft disposed in a bearing nip of a support-disk bearing, the brake comprising at least one brake lever having a brake lining comprised of sintered bronze, the brake lever being disposed for selective braking movement into and out of engagement with the rotor shaft.
 2. The brake according to claim 1, wherein the brake lining is fixed to the brake lever via a detachable fastener assembly for selective replacement.
 3. The brake according to claim 2, wherein the brake lining comprises a fastening slot open at the bottom into which extends a centering extension of the fastener assembly in an assembled state. 